diff --git a/include/battle_util.h b/include/battle_util.h
index 4dac63111a..26bfe3c7ce 100644
--- a/include/battle_util.h
+++ b/include/battle_util.h
@@ -151,6 +151,7 @@ void SortBattlersBySpeed(u8 *battlers, bool8 slowToFast);
 bool32 CompareStat(u8 battlerId, u8 statId, u8 cmpTo, u8 cmpKind);
 bool32 TryRoomService(u8 battlerId);
 void BufferStatChange(u8 battlerId, u8 statId, u8 stringId);
+void DoBurmyFormChange(u32 monId);
 
 // ability checks
 bool32 IsRolePlayBannedAbilityAtk(u16 ability);
diff --git a/include/constants/battle_config.h b/include/constants/battle_config.h
index edf1cbb4fb..b2559dbb7f 100644
--- a/include/constants/battle_config.h
+++ b/include/constants/battle_config.h
@@ -37,6 +37,9 @@
     #define SPECIES_ZYGARDE                 0     // 50%
     #define SPECIES_ZYGARDE_10              10011 // 10 %
     #define SPECIES_ZYGARDE_COMPLETE        10012 // 100 %
+    #define SPECIES_BURMY                   0
+    #define SPECIES_BURMY_SANDY_CLOAK       10013
+    #define SPECIES_BURMY_TRASH_CLOAK       10014
 #endif
 
 // Items with peculiar battle effects.
diff --git a/src/battle_main.c b/src/battle_main.c
index 17322e5cd2..72d05a0fd0 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -4897,6 +4897,7 @@ static void HandleEndTurn_FinishBattle(void)
         {
             UndoMegaEvolution(i);
             UndoFormChange(i, B_SIDE_PLAYER, FALSE);
+            DoBurmyFormChange(i);
         }
         gBattleMainFunc = FreeResetData_ReturnToOvOrDoEvolutions;
         gCB2_AfterEvolution = BattleMainCB2;
diff --git a/src/battle_util.c b/src/battle_util.c
index ccc0c558a8..dfbdd79552 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -9170,3 +9170,43 @@ bool32 TryRoomService(u8 battlerId)
         return FALSE;
     }
 }
+
+void DoBurmyFormChange(u32 monId)
+{
+    u16 newSpecies, currSpecies;
+    s32 sentIn;
+    struct Pokemon *party = gPlayerParty;
+
+    sentIn = gSentPokesToOpponent[(gBattlerFainted & 2) >> 1];
+    currSpecies = GetMonData(&party[monId], MON_DATA_SPECIES, NULL);
+
+    if ((GET_BASE_SPECIES_ID(currSpecies) == SPECIES_BURMY) && (gBitTable[monId] & sentIn))
+    {
+        switch (gBattleTerrain)
+        {  
+            case BATTLE_TERRAIN_GRASS:
+            case BATTLE_TERRAIN_LONG_GRASS:
+            case BATTLE_TERRAIN_POND:
+            case BATTLE_TERRAIN_MOUNTAIN:
+            case BATTLE_TERRAIN_PLAIN:
+                newSpecies = SPECIES_BURMY;
+                break;
+            case BATTLE_TERRAIN_CAVE:
+            case BATTLE_TERRAIN_SAND:
+                newSpecies = SPECIES_BURMY_SANDY_CLOAK;
+                break;
+            case BATTLE_TERRAIN_BUILDING:
+                newSpecies = SPECIES_BURMY_TRASH_CLOAK;
+                break;
+            default: // Don't change form if last battle was water-related
+                newSpecies = SPECIES_NONE;
+                break;
+        }
+
+        if (newSpecies != SPECIES_NONE)
+        {
+            SetMonData(&party[monId], MON_DATA_SPECIES, &newSpecies);
+            CalculateMonStats(&party[monId]);
+        }
+    }
+}